Vehicle position indicator



Nov. 28, 1961 H. J. RUMRILL ET AL 3,010,329

VEHICLE POSITION INDICATOR 2 Sheets-Sheet 2 Filed June 18, l958INVENTOR5 HOWARD J. RUMRILL EDWIN w HOWE 2 y W4 ATTOPNEK 3,010,329Patented Nov. 28, 1961 3,010,329 VEHICLE POSITION INDICATOR Howard J.Rumrill, Mineola, and Edwin W. Howe, North Baldwin, N.Y.; said Rumrillassignor to American Bosch Arma Corporation, a corporation of New YorkFiled June 1a, 1958, Sex. No. 742,849 3 Claims. c1. 74-198) venience. Inoperation, the rectangular coordinates of the initial position are setinto mechanical counters in each of the two major units. The vehicleposition computer includes a mechanical resolver-integrator havinginputs according to the heading from a gyro compass and speed from thevehicle odometer, which provides outputs proportional to the distancestraveled by the vehicle in the north and east directions. The mechanicalcounters of the vehicle position computer are operatively connected tothe resolver-integrator outputs so that the counters indicate thepresent position coordinates.

The mechanical counters of the distance and bearing computer are alsodriven according to the mechanical resolver-integrator outputspreferably through an electromechanical link, such as a step motor, forexample. The distance and bearing computer contains another set ofcounters on which the coordinates of the destination are manuallyinserted. The rectangular coordinates of the distance between thepresent position and destination are obtained by mechanicaldifferentials connected to theappropriate counters. Electrical signalsproportional to these rectangular coordinates are obtained frompotentiometers driven by the mechanical differentials and the signalsare applied to an electromechanical resolver to obtain the vector valuesof distance to go and true bearing to destination in thewell-known'manner. heading of the vehicle and the bearing tothedestination are displayed simultaneously on the same instrument.

The mechanical resolver-integrator used in the vehicle position computeris one of the ball-type resolvers whose theoretical aspects are Wellknown in the art. However, the particular component to be described herehas been specially designed as a miniature, dependable, accuratecomponent and is preferable to others of the same class. Theimprovements in the ball resolver of preferred choice will be fullydescribed in the following.

For a better understanding of the invention, reference may be had to theaccompanying diagrams, in which:

FIG. 1 is a schematic diagram of the vehicle position indicator;

FIG. 2 is a representative coordinate map;

FIG. 3 is a section of the ball resolver-integrator; and

FIG. 4 is another section of the ball resolver-integrator.

The vehicle position indicator of FIG. 1 requires geographicalinformation in the form of grid coordinates rather than latitude andlongitude. FIG. 2 shows such a grid reference by which geographicallocations are identified by rectangular coordinates. Thus, the positionP is designated as 5432 north and 5678 east, while theposition D isdesignated as 9876 north and 2345 east. The actual grid is much largerthan FIG. 2 and the lines are closer For convenience, the v spaced thanshown in FIG. 2, so that the four place readings of position are easilydetermined.

The position indicatorof FIG. 1 comprises two units; one, above thedotted line, is the vehicle position computer, and the other, below theline, is the remote destination bearing and distance computer.

The vehicle position computer includes a mechanical resolver-integrator11 of advanced design having a pair of concentric inputs 10 and 12 whichare respectively driven according to the speed of the vehicle anddisplaced according to the heading of the vehicle.

The mechanical resolver-integrator of preferred design is detailed inFIGS. 3 and 4. This preferred construction permits manufacture of aprecision component in a minimum size. With reference now to thesefigures, the resolver-integrator 11 includes a ball 15 which is urgedagainst a pair of perpendicularly disposed output rollers 16 and 17, byan idler roller 18. The roller 18 may be a ball bearing mounted on ashort shaft in the member 19, which member is pivoted in frame 20 at aand is urged toward the ball 15 by the tension spring 21 connectedbetween pins on member 19 and frame 20. Rollers 16, 17 and 18 arepositioned so that their points of contact are all in the sameequatorial plane of ball 15, and their planes of rotation areperpendicular to that equatorial plane.

The outer coaxial input shaft or cage 12 is journalled in bearing 28 inthe frame 20, and carries at its inner end a shaft 22 which isjournalled in the bearing 23. The inner coaxial input shaft 10 isjournalled in bearings 27 within the cage 12 and carries at its innerend a bevel gear 26. The bevel gear 26 meshes with a bevel gear 25 onshaft 22, on which a roller 24 is also mounted. Thus, the roller 24 isdriven at a speed proportional to the speed of rotation of input shaft10, and the axis of rotation of the roller 24 is controlled'by theangular position of cage 12.

The rotation of roller 24 is transferred to the ball 15 by urging theball 15 against roller 24 by means of the coil spring 37 and the roller35, as will be described. In the interest of accuracy it is imperativethat the idler roller 35 be forced to rotate in the same plane as theinput roller 24 so that the ball 15 will rotate about an axis parallelto the rotational axis of the roller 24. To this end the cage 12 and thecollar 33, in which roller 35 is mounted on shaft 34, are geared torotate together. Thus, gear teeth 29 are formed on a projection on cage12 and are adapted to mesh with the teeth of gear 30. Gear 30 isattached to a stud shaft 31 which is rotatable in bearings (not shown)in the frame 20. The lower end of shaft 31 carries a gear 32 whichmeshes with gear teeth formed on the flange of the collar 33. Gearing 30and 32 are preferably split gears in order to minimize the backlashbetween the gears on cage 12 and collar 33.

Roller 35, which may be a ball bearing, for example, is mounted on ashaft 34 in the collar 33. The collar 33 is journalled in bearing 36which provides longitudinal as well as rotational freedom in frame 20,and is urged toward ball 15 by the coil spring 37 located between thecollar 33 and the hub 38. I

Thrust bearings 39 and 40 between the frame 20 and, respectively, thehub 38 and cage 12 assure free rotation of these elements.

For precision, the rollers 16 and 17 must contact ball 15 at positionsprecisely apart. To this end the shafts 41 and 42, to which rollers 16and 17 are attached, are journalled in bearings 43, 44 and 45, 46respectively at the extremities of the precisely bored holes 47 and 48in the frame 20. The perpendicularity of the holes 47 and 48 can bemaintained to a high degree of accuracy during manufacturing processesthereby insuring the perpendicularity of shafts 41 and 42 in theassembled component.

In further attempt at miniaturization it has been found advantageous tousereduct-ion gearing between the input shaft and the ball 15, and touse an inverse ratio between diameters of the ball and the outputrollers. Thus, in the preferred embodiment the speed ratio between gears26 and 25 is 3 :2 while between ball 15 and either of rollers 16 and 17it is 2:3.

Returning now to FIG. 1, the shaft 10' is driven from the vehicleodometer at a speed of nominally one thousand revolutions per statutemile of travel of the vehicle. The speed changer t) permits anadjustment of the actual odometer output to correspond to the nominalinput to the resolver-integrator 11. The cage 12 is driven by the gyrocompass 13 through gearing 14 to adjust the axis of rotation of theroller 24 (FIG. 3) to correspond to the course of the vehicle. Thus, asin the well-known manner of prior mechanical resolver-integrators of theball type, the speed and heading values are integrated and composed intodistance traveled north at shaft 41 and distance traveled east at shaft42.

Shaft 41 is operatively connected to drive a generator 51, the outputsignal of which is thus proportional to the velocity in the north-southdirection. This signal is used to provide the correction of the gyrocompass 13 for the north steaming error in the manner described in US.Patent 2,677,194, for Gyroscopic Compass, for example.

Shafts 41 and 42 also drive the mechanical counters 52 and 53respectively to insert into the counters the distances traveled northand east by the vehicle. The counters 52 and 53 are initially set byknobs 54 and 55 and the disconnecting clutches 56, 57 to the initialposition of the vehicle so that the readings of the counters alwaysindicate the coordinates of the present position of the vehicle, whichmay be position P of FIG. 2, for example. The clutches permitpositioning of the counters without driving the shafts 41 and 42.

The distances traveled by the vehicles north and east are transmitted tothe remote destination bearing and distance computer by any convenientmeans, either electrical or mechanical. FIG. 1 shows an electrical linkwhere the step transmitters 58 and 5 are operatively connected to shafts41 and 42 respectively and electrically connected to the respective stepreceivers 60 and 61. Receivers 6t and 61 are adapted to drive thecounters 6'2 and 63 respectively through the clutch mechanisms 64 and 65by means of gearing 66 and 67. The initial position of the craft isinitially inserted in the counters 62 and 63 by means of knobs 68 and69. Switches 70A and 71A, actuated when knobs 68 and 69 are operated,disengage the clutches 64 and 65 so that the adjustment of counters 62and 63 can be done without adjusting the receiver motors 60 and 61. Thedistances traveled by the vehicle are set in the counters by the motors6t} and 61 so that the counters 62 and 63 continuously display thepresent position of the vehicle.

The north and east coordinates of the destination D (FIG. 2) of thevehicle are normally set in the counters 70 and 71 by the knobs 72 and73 and are then locked in position, as by brakes 74 and 75, for example.A mechanical differential 76 is adapted to drive an output shaft 78according to the difference in the displacements of the counter-drivenshafts 62a and 70a so that the displacement of shaft 78 represents thedistance to go in the north direction to reach the destination D.

Similarly, the output shaft 79 of the differential 77, connected to theshafts of counters 63 and 71, is displaced by an amount proportional inmagnitude and sign to the distance to go in the east direction to reachthe destination D.

The displacements of shafts 78 and 79 are transformed into proportionalelectrical signals in the potentiometers 80 and 81 respectively, or inany equivalent element for the same purpose. The outputs ofpotentiometers 80 and 81 energize the input windings 82 and 83 of anelectromechanical resolver 84, which is shown in FIG. 1 as aninduction-type resolver, but is not necessarily limited thereto.

The resolver 84 is adapted to compose the north and east components ofthe distance to go to destination into vectorial quantities of truebearing of the destination and the distance to the destination.

Thus, one output winding 85 is connected to a motor 86, through anamplifier 87, and the motor drives the winding 35 by means of the shaft83 until the voltage energizing motor 86 is zero. Shaft 83 also drivesone pointer 39 on a display dial 9 0 to indicate the bearing of thedestination D.

The output of the other winding 91 of resolver 84 is proportional to thedistance to go to destination. The output of winding 91 is matchedagainstthe output of a potentiometer 92 and the error signal is appliedto a motor 93 through amplifier 94. Motor 93 drives shaft 95 and therebyadjusts potentiometer 92 until the error signal is zero so that thesetting of the potentiometer 92 until the error signal is zero so thatthe setting of the potentiometer represents the distance to go todestination. This distance to go is displayed on the counter 96 which isalso connected to the shaft 95.

The bearing display preferably also indicates the present heading of thevehicle by a second pointer 97. This pointer is positioned by compass 13through the telemetering link including a synchro generator 98operatively connected to the gyro compass 13 by gearing 14 andelectrically connected to the synchro receiver 99 whose shaft 1% drivesthe pointer 97. The operator of the vehicle steers the vehicle in thedirection which brings the pointer 97 closer to pointer 89, and when thepointers 97 and 89 are in register the vehicle track will lead directlyto the destination. Usually, however, the terrain will permit only areduction of the separation between the pointers 97 and 89 to a minimum.

We claim:

1. In a device of the character described, a pair of concentric inputs,a pair of perpendicularly disposed output rollers, a ball, and an idlerroller urging said ball against said output rollers, the outer of saidinputs having a transverse shaft adjacent its inner end, the inner ofsaid inputs carrying a bevel gear adjacent its inner end, a bevel gearon said transverse shaft meshing with said bevel gear on said innerinput, a roller on said transverse shaft, said roller being driven at aspeed proportional to the speed of rotation of said inner input and theaxis of rotation of said roller being controlled by the angular positionof said outer input, said output rollers and idler roller being sopositioned that their points of contact with said ball are all in thesame equatorial plane of said ball and their planes of rotation areperpendicular to said equatorial plane, a second idler roller oppositesaid roller on said shaft, said second idler roller being mounted on acollar, gearing between said collar and said outer concentric input tokeep said second idler roller and said roller on said transverse shaftin the same plane, and resilient means for urging said collar towardsaid ball.

2. In a device of the character described, a pair of concentric inputs,a pair of perpendicularly disposed output rollers, a ball, and an idlerroller urging said ball against said output rollers, the outer of saidinputs having a transverse shaft adjacent its inner end, the inner ofsaid inputs carrying a bevel gear adjacent its inner end, a bevel gearon said transverse shaft meshing with said bevel gear on said innerinput, a roller on said transverse shaft, said roller being driven at aspeed proportional to the speed of rotation of said inner input and theaxis of rotation of said roller being controlled by the angular positionof said outer input, said output rollers and idler roller being sopositioned that their points of contact with said ball are all in thesame equatorial plane of said ball and their planes of rotation areperpendicular to said equatorial plane, a second idler roller oppositesaid roller on said shaft, said second idler roller being mounted on'acollar, gearing between said collar and said outer concentric input tokeep said second idler roller and said roller on said transverse shaftin the same plane, and resilient means for urging said collar towardsaid ball, said bevel gearing between said inner input and saidtransverse shaft being reduction gearing.

3. In a device of the character described, a pair of concentric inputs,a pair of perpendicularly disposed output rollers, a ball, and an idlerroller urging said ball against said output rollers, the outer of saidinputs having a transverse shaft adjacent its inner end, the inner ofsaid inputs carrying a bevel gear adjacent its inner end, a bevel gearon said transverse shaft meshing with said bevel gear on said innerinput, a roller onsaid transverse shaft, said roller being driven at aspeed proportional to the speed of rotation of said inner input and theaxis of rotation of said roller being controlled by the angular positionof said outer input, said output rollers and idler roller being sopositioned that their points of contact with said ball are all in thesame equatorial plane of said ball and their planes of rotation areperpendicular to said equatorial plane, a second idler roller oppositesaid roller on said shaft, said secondidler roller being mounted on acollar, gearing between said collar and said outer concentric input tokeep said second idler roller and said roller on said transverse shaftin the same plane, andresilient means for urging said collar toward saidball, said bevel gearing between said inner input and said transverseshaft being reduction gearing, the ratio between said output roller andsaidball being the same as between said input and said transverse shaft.

References Cited in the file of thispatent UNITED STATES PATENTS1,701,582

